In surgical procedures, it is preferable to minimize or reduce trauma to the patient and damage to tissue. To achieve this result, surgeons try to keep incisions as small as possible. However, it is usually necessary that the surgeon have a clear view of the operating field.
A variety of retractors are available to keep an incision open and provide a clear view of the operating field. Retractors are used in surgical operations to reposition muscular tissue, vessels, nerves, and other tissue with the aid of retractor blades, thereby providing access to the site of the operation. Surgical retractors are particularly important in performing surgical procedures that involve the spinal column, where access to the surgical site can be obtained, for example, through a posterior, posterior-lateral, anterior, lateral, or an anterior-lateral approach.
Retraction can be performed in a variety of ways. In some embodiments, a step-wise dilation of the surgical incision can be performed to gradually dilate the muscles and tissues to the required size to insert the retractor. Step-wise dilation can involve the use of a series of dilators or cannulae with successively larger diameters. This method involves first inserting the smallest dilator or cannula into an incision. Then a second dilator or cannula, with a slightly larger diameter, is slid over the smaller dilator or cannula and into the incision, thereby causing the incision to expand to the slightly larger diameter of the second dilator or cannula. This process can be repeated using a series of dilators or cannulae with successively larger diameters, until the incision is large enough to allow for insertion of the retractor. Once positioned, the retractors produce a small surgical site or window.
In some embodiments, a retractor can include multiple blades attached to a frame. The blades can be inserted into tissue and moved apart from one another to retract the tissue. However, moving the blades apart from one another can be cumbersome depending on where access to the surgical site is obtained, e.g., awkward positioning of the surgeon relative to the retractor during lateral approach to a spine. It can also be difficult to adjust the blades to a particular desired position without moving the blades apart from one another too much, thereby causing problem(s) such as harming nearby tissue or pushing against a nerve.
Accordingly, a need exists for improved methods and devices for tissue retraction.